Comment by digikata
This seems around the durability that most databases can reach. Aside from more specialized hardware arrangements, with a single computer, embedded database there is always a window of data loss. The durability expectation is that some in-flight window of data will be lost, but on restart, it should recover to a consistent state of the last settled operation if at all possible.
A related questions is if the code base is mature enough when configured for higher durability to work as intended. Even with Rust, there needs to be some hard systems testing and it's often not just a matter of sprinkling flushes around. Further optimization can try to close the window tighter - maybe with a transaction log, but then you obviously trade some speed for it.